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Thus it is recommended to determine distance between gear axis: A = t3 • n3/cosas-8A, (7)
where, t3 - is the step of between teeth of gean; n3 - number of sections in the branch of trailing gear.
To get solutions as per expressions (5), (6), (7) the calculation parameters are taken in the following values:
t3 = 15.0 -21.0 mm.; nl = 200 - 400min.-1;[P] = 28 -31MPa; n = 938, z1 = 22, Z2 = 25; r2 = (5.5 - 6.5) • 10 2 m; m2 = 0.015 * 0.035kg.
In the fig. 2a the chain transmission trailing gear deformation force is shown in values generated in additional tension. The obtained diagram connections show that the increase of angle speed brings to nonlinear decrease. The tension belt working in transmission brings to increase Q force. When additional tension force increases from 60 H. to i05 H. and the difference between force is = 18c 1 and when 4.15 • 102H is generated by it is generated pro ratio.
The main reason for it is the tension rolling influence in rotating frequency is not high, i. e. in this the momentum role is increased. It is necessary to state that the force which deforms flexible element by increasing radius of gear. We can see it the diagram already reviewed before. This law can be explained as follows. When the branches of chain the more its momentum force i. e. it decreases deformation force of flexible element. However, the long term operation of transmission is affected by deformation of flexible element. The deformation around axis of chain transmission with trailing element to be avoided from increase 2.0 V 3.0 mm when radius of gear is r2 = (5.5^6.5)-10 2m it is good select (3.2 ^ 5.4) -105 N / m . It is necessary to state that trailing gear shaft is working body connected with plug drum. Resistance fluctuation is decreased significantly at the expense of flexible element. I. e. vibration coming from clay brick to chain come with decreased force.
1 - AF? = 105N;2 - AF? = 80N; 3 - AF? = 60N
1 -m2 = 0.015kg; 2 - m2 = 0.025kg; 3 - m2 = 0.036kg.
Fig. 2. a - Diagram of chain transmission connected with angle speed; b - diagram bound with change of radius force and deformation of flexible element
References:
Glushenko I. P., Semenov, Lysenko. About determining of minimum tension of chain loose side of chain transmission//Mechanical transmissions. - Tr. Kubanskiy institute, 1976. - P. 31-37.
Gotovtsev A. A. Chain transmissions and chain equipment elements/A. A. Gotovtsev, G. B. Stoblin//Machine parts. Calculation and construction: Reference book T. A./under edition N. S. Acherkana. - M.: 1969. - P. 279-345.
Khakimov Zafar,
Vice rector of the Tashkent University of Information Technologies,
Ph. DDoctor of Philosophy E-mail: [email protected]
Research and application of acousto-optical tunable filters for modern telecommunications systems
Abstract: In article are considered integrated acousto-optical tunable filters, the analysis of possibility of adjustment of the surface acoustic wave is carried out and acousto optical conversion of modes on their basis, integration of optical technologies also is inspected.
Keywords: Acoustic waves, Electro-optical tunable filter (EOTF), Acusto-optic tunable filter (AOTF), Optical and Acoustic beam, interdigital transducer (IDT).
The idea of acousto-optical tunable filters (AOTF) was pro- are inspected according to them, the surface acoustic wave and
posed in 1969 by Harris and Wallace [1] and was demonstrated by acousto-optical mode conversion is analyzed as well as the inte-
Harris and his colleagues. The flat (planar) integrated elements of grated optical technology is considered.
acousto-optics, including filters, frequency switchers and modula- The processes involved in the work AOTF are quite com-
tors have been discussed in [2]. In this paper, the integrated AOTF plex. The piezoelectric wave linked to a surface acoustic wave can
Research and application of acousto-optical tunable filters for modern telecommunications systems
produce secondary periodic electro interaction. This acoustic-electro optical interaction complicates the relatively simple batch representation induced birefringence, but a detailed source of effective acousto-optical interaction does not work at the primary frequency.
The development evolution of AOTF is presented in Table 1. The evolution progress was manifested in the movement from the volume of the optical wave and an acoustic wave to the volume of serial narrowing optical and acoustic rays to reduce the requirements for the power (energy) and to increase the interaction length.
Ohmashi and Noda used flat (planar) optical waveguides and surface acoustic wave in the first version of an integrated optical filter. The approach by Binh and his colleagues is limited to optical beam in single-mode optical waveguides and lowered power consumption by limiting the surface acoustic wave. Hink has been a pioneer in the use ofpatch installation laser for optical and acoustic waveguide. Goto developed the acousto-optic spatial mode converter, which had the same principle of phase comparison, as polarization mode converters, but this device is guided the filtered and unfiltered components to various waveguides [3].
Table 1. - Development evolution of AOTF
Date Author Development
1970 Harris Volumetric Optical AOTF
1977 Ohmachi and Noda Planar optical, IR filter
1980 Binkh and Livingston The channel acousto-optical waveguide low power
1983 Goto Spatial converter AOTF
1985 Khinkov The technique of proton exchange
1988 Heffner Frequency division for integrated optics
1989 Cheyung The use of multi-frequency switching systems
1989 Smith Highly integrated AOTF
AOTF can be performed based on various materials. Table 2 shows the characteristics of AOTF on the basis of a single crystal of quartz, Tantalus-lithium, and Niobe-lithium.
In the development of counter-doweled transducer (IDT) on the harmonics of the fundamental frequency, the response method is used piecewise approximation instead of synthesizing a smooth
Table 2. - Technical
envelope of the impulse. This approximation is accurate enough when working on harmonics 3, 5, 7 in the synthesis of narrow-band (less than 2 % for niobate LiNbO3 and Tantalus-lithium, less than 0.5 % for the silica and zinc oxide films) filters with the most common designs suggesting GSW, transducers with capacitive weighing electrodes [4]. characteristics of AOTF
Parameter Units The single-crystal quartz Tantalate Lithium Niobate-Lithium
Spectral range nm. 750 ... 850 1000 ... 1150 1500 ... 1700
The range of frequency control MHz. 600 ... 690 430 ... 500 100 ... 250
Input window mm. 4 x 4 4 x 4 4 x 4
Input angular aperture Deg. 2.8 3.4 2.2
Maximum driving power W. 3 3 3
The diffraction efficiency %/nm/W 20/800/1 15/1150/1 7/1550/1
Impedance Om. 50 50 50
On the basis of the data in Table 2 it can be concluded that the most promising acousto-optical filters are AOTF based on niobate-lithium, which has the best technical parameters for use in fiber-optic data transmission systems (FDTS), and can improve the spectral characteristics of the emitted signal.
All integrated optical AOTF listed above should have some form of fiber, to be compatible with fiber optic communication networks, but one group bypassed the fiber compound, the problem by making a AOTF compatible with all types of fibers.
Narrowband mode conversion is achieved using a birefringent acousto-optic interaction medium. In this environment, the two polarization components — TE (horizontal) and TM (vertical) — and fall out of phase with the intrinsic beating length:
Lbieny ^/An , ( l)
where An — material birefringence; ^ — emission wavelength.
Ifthe applied DC voltage, the photoelastic effect produces a consistent TE — TM transformation and reverse transformation to a half wavelength, producing very little conversion for interaction lengths more L — in fact, the resulting effective length of the element has
hieny ' c c
a uniform voltage across its length and in most cases is Lhky /2, regardless of the length of material interaction. The only way to produce transformation events is to alternate the polarity of the voltage synchronously with the relative stage variable orthogonal polarizations.
The AOTF is achieved by moving the acoustic wave. The exact criteria for constructive interference or appropriate stage could be the fact that the wavelength of sound is equal to the length beats ^ , =L. . This leads to an equation relating the electrical frequency
ak hieny 1 c 1 '
f and a favorite source of wavelength
fo = (Vound ^A, (2)
where V , — speed of sound, An u— the difference between the
sound L ' eff
effective indicators.
An overall idea of a filter band width should be of constructive interference immunity test. The increment of wavelength is required to complete destructive interference, such that the first half of device interaction is in phase, while in the second half of device interaction is shifted in phase, leading to the complete quenching mode conversion.
This suggests the characteristic parameter band width of the filter:
A = A 2/LAn. (3)
Fig. 1 shows a linear scale of the ideal transfer characteristic AOPF proportional to the square of the sinus.
If conversion is incomplete, the filter band width and sidelobe spectrum changes. The intensity (strength) of the side lobes in this case is relevant to the inter-channel interference for the operation of a multiple wavelength AOTF.
Fig. 1. Characteristic of ideal AOTF
^e gain of the ideal AOTF as a normalized function of the wavelength can be represented as an analogue electro-optic tunable filter (EOTF) [5], because the physics of the two devices (elements) is very similar. AOTF and EOTF have the same optical transmission as a function of wavelength, but they differ in two important features. AOTF reached an appropriate stage through periodic electrodes and An is adjusted only slightly, leading to a modest adjustment range. ^e filter described in [6] only a tuning range was 15 nm., as offset adjustment — DC voltage. AOTF can filter only one band of the wavelength at a time, making it more versatile AOTF.
^erefore, for use in the AOTF in IDT it must have the ability to switch any number of channels (operating at different frequencies) simultaneously and independently of each other. ^e lightweight set-up and strengthening of the optical radiation of either is discussed in [7], [8] and [9].
To calculate the characteristic AOTF, the following relationship is used:
14
H(a) - S(-1)"«0 exp(-jaTn) = «0 -«0 exp(-jT + «„ -
n-0
-ao exp(ja2To) +... + atl - atl exp(-ja14To) -1 - exp(-jaT /14 +. (4) + exp(- ja2T/14) +... + exp(- ja14T/14)
Uis equation can be written as follows:
14
H(a) = X(-1)"a0 [cos a>Tn - j sin a>Tn ] =
n=0
14 14
= ^(-1)na0 • cosaTT - j 'Y,(-1)"a0' sina>Tn.
n=0 n=0
To calculate the module (i) AOTF characteristics:
(5)
H = H(w) = • coswTn j + j^X(-1)X • sinwTn | . (6)
To calculate the argument (9) characteristics AOPF:
$ — H(w) - arctg-
^(-l)"a0 • cos öT-
. n-0_
14
ZH)X • sin û)T
(7)
According to these calculations, for the wavelength \ = 1.55 microns most optimal number of pins turned 14 at the given size pin height of 1 mm., the distance between the electrodes is 1 mm and a thickness of 0.5 mm.
^ese discussions hava the following key benefits: 1) wide tuning range (200 nm.); narrowband; short switching times;
Most importantly, the ability to switch between any number of channels (operating at different frequencies) simultaneously and independently of each other. ^e lightweight set-up and amplifiers; ^e ideal selectivity. In addition, the use of amplifiers, frequency acousto-optic tunable filters have almost rectangular amplitude-frequency characteristic (AFC) and provide the ideal selectivity, good mass and dimensions parameters as well ass ease of configuration and adjustment of the amplifiers.
Also the set of main features of the characteristics, parameters and properties of AOTF are used in high-speed fiber-optic data transmission systems.
Uus, it is shown that the most promising acousto-optical filters are AOTF based on niobate-lithium, that have the best technical parameters for use in IDF and can improve the spectral characteristics of the emitted signal.
2)
3)
4)
5)
References:
Harris S. E. and Wallace R. W. Acousto-Optic Tunable Filter//J. Opt. Soc. Am. - 1969. - V. 59. - P. 744-747.
Ohmachi Y. and Noda J. LiNbO3 TE-TM Mode Converter Using Collinear Acousto-Optic interaction//IEEE J. Quant. Electron. -
1977. - v.Qe-13. - P. 45-46.
Su S. F., Olshansky R., Smith D. A. and Baran J. E. Gain Equalization in Multiwavelength Lightwave Systems Using AcoustoOptic Tunable Filter//IEEE Photonics Technology Letters. - 1992. - V. 4, No 3. - P. 269-271.
Khakimov Z. T. Features ofAOTF. In lecture notes collection of PhD, master and bachelor students - scientific-technical information-communication technologies. 4-5 march 2008. - Tashkent. - P. 133.
Surface acoustic waves. Reviewer A. Olinera. Trans. from English. Ed. I. S. Reza - M.: Mir, 1981. - 392 p.
Baghdasaryan A. S. Impedance SAW filters for mobile communication systems//Systems and communications, television and radio. -M., 1998. - Vol. 1.
Radzhabov T. D., Davronbekov D. A. and Khakimov Z. T. Studies of the spectral characteristics of optical signals using AOTF in IDF// Infocommunication: Network-Technology-Solutions. - Tashkent, 2008. - № 1(5). - P. 3-7.
Radzhabov T. D., Davronbekov D. A. and Khakimov Z. T. Optimization of the spectral characteristics of the fiber optic link//Bulletin TUIT. - Tashkent, 2009. - № 2. - P. 62-65.
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